The invention starts from a method for dry-heat sterilization of heat-tolerating containers under clean-room conditions, in particular glass bottles for filling with pharmaceutical products, wherein the containers are, via laminar flow units, continuously moved into and out of a radiant oven and are then cooled by HOSCH-filtered air, a part of the HOSCH-filtered air being branched off at the outlet of the radiant oven and being passed in a controlled low-turbulence displacement flow through the radiant oven.
A method of this type with the associated radiant oven has been described in German Patent 2,631,352, the U.S. counterpart being U.S. Pat. No. 4,140,479 to Edgar Sirch et al, dated Feb. 20, 1979. The sterilization method described therein has proved itself by and large if, with respect to the maximum permissible particle count, the requirements of class 100, US Federal Standard 209 b (or approximately class 3 VDI 2083) are to be fulfilled.
Furthermore, the new edition of this standard, also relevant to pharmaceutical production (US Federal Standard 209 c), also defines the higher-grade class 10 which is to be met by the radiant oven described.